Samuel i



filing" f Letters1 Patent JNO. 104,511, dated Juno 21, 1.870.

STEAM-GENERA'IYQR.

The Schedule referred to in these Letters Patent; and making part of the same Tc "all whom 'it may concern: v

` Be itknown that I, SAMUEL D. TILLMAN, of J ersey City, in the county ot' Hudson and State of New Jersey, have invented certain new and useful Improvements in Steam-Boilers; and I do hereby deelare that the following `is a full and exact description thereof. s .I will first describe what lconsider the best mean's of carrying out my invention, and will afterward designate'the points which I believe to be new therein.

. The accompanying drawing foi-insa part of this specification.` Figure 1 is across-section, and` Figure 2 is another, the iirst'being on` the line '.l T, fi 2, andthe second on the line S S, grl. f The additional gures are only of importance in illustrating modifications of portions o f my apparatus. SimilarA letters of reference indicate corresponding parts in both the figures. l Y 'lhe drawing represents the'I novel parts, with so inucli ofthe ordinary parts as seems necessary to indicate their relation thereto. p l

G is al stout plate of iron,i`ormin'g the bottom of 1n y boiler, and i H is a corresponding plate forming the top thereof. M is a cylindrical shell, which joins the bottom G with the top H, and forms, with the said top and bottom, an npriglit cylindrical boiler-shell, having the` strength and other qualit-ies necessary to resist the pressure of the steam.

B lil, Sac., are tubes, extendin glongitudinall y through the boiler, and set inthe upper and lower 'ends in the ordinary or any suitable manner, to allow a portion of the products of combustion to pass' vthrough these tubes and impart their heat' to the water.

The tubes B-are arranged in a circle or series. 1 have represented six, but the number may be increased or diminished without losing all tlie'advant-agcs of my invention. It is important that they be arranged in av circular series, each at a proper distance both from the center and the 'circumference of the cylinder, as will presently appear. f D D are plates of wrought iron, or other suitable material, mounted on the tubes B, and standing oblique- A.

ly' across, as represented. They may be secured in any ordinary or approved manner, as, for example, welding, brazing, or soldering, and they may be formed of such size, and -so arranged as to match cach other edge to edge, that is to say, the edges of the .plates D on one pipe, B, may coincide with the edge of the plates D on the adjacent tubes B, but this condition is not absolutely essential to the successof my invention.

The degree of inclination of my plates D may be varied.V Instead of making them absolutely plane,

they may be curved, as indicated in Figure 5, or they may be curved in the other direction, so that a series of plates extendinghorizontally around iu the intcrioi `of the boiler, coinciding at their cdgcs,as represented, may present the contour of a segment of a cone, nistead of the segment of a pyramid, which latter forni will result from the use of plane plates.

Various other variations may be made by' any good mechanic, without departing from the principle or destroying the beneficial effect of my invention.

lVhen my boiler is set in brickwork,1 leave alittle space, say one inch, more or less, between tho exterior ol' the cylindrical surface Maud the interior oi' the brick-work. The boiler having been filled with water to a proper extent, and provided with suitable connections for thc discharge of the steam, andA for supplying, feed-water, as will be obvious,a fireis maintained below on any ordinary and suitable grate, and

a portion of the draught is allowed to flow upward through the pipes B, while another portionjs allowed to rise inthe narrow annular space around the extcf rior.

Undcr'these oi any analogt'ius` conditions my plates l) perform `important functions, both by increasing the heating-surice and deileciing the currents of water andsteam. As tubes in upright boilers have been heretofore generally arranged, the steam produccdou the lower -portion of any tube rises in contact with the tube and partially or entirely prevents the access of thc dense water to the upper portion ofu the tube.

In my improved boiler, the particles of steam generated below any given plate D risesdirectly, dragging the surrounding water with them, until they 'stgike the said plate, and are thereby deflected outward, while dense waterirom near the axial liuc of the boiler iows outward, to take the place of the water-so removed to bec6mc,in its turn', partially changed into steam, and risc and move outward.

When, as' above provided, cylindrical shell Mis also` a heating-surface,the steam generatedl on its inner surface also rising, generates an active upward current around the entire circumference of the boiler.

On reaching the water surface, the particles of steam arcliberated, a current of watci' l'lows inward from all sides, and descends in thc center of the boiler. In its descent it supplies the several spaces bc tween the plates D with an outgoing current of water, and thus an active round or circulation obtains.

Que new result obtained by my tubes, covered with a series of projections or plates, D, is that steam will be nrenerated faster than by plain tubes, through which the liet productsof combustion are passing. The temvperature of my tubes cannot be raised to such a point that steam. will not be generated freely,since `the out-` side transverse plates or projections are rapidly con' ducting the heat from the tube itself and`preventing its being overheat-ed.

It seems now to be well settled that steam is gencrated mest rapidly at a degree of temperature far be- 4 Vbe covered with radial projections, which would not seriously retard the circulation of the descending water, but it is most feasible and economical to place a non-conducting substance, like soapstoue, under the bottom, having in it holes corresponding with the lower ends of the tubes, so as to allow the heat to pass into the tubes.

I propose, in some cases, te use one of these tubes,

B, with its plates, D, mounted centrally in a larger tube, a series of which larger tubes properly constructed shall form a boiler; and in some cases the attached plates or projections on the tubes may forni crescent-shaped opening above and below, and the whole may be cast together. This will increase its strength.

Figure 3 represents such aeast-iron section, having an inclined position, and

Figure 4, a cross-section on line M in tig. 3, showing how the water passes under the central tube and the steam above it. A

rlhc plates D D may also be used Von horizontal tubes in a horizontal boiler, for the purpose ofiucreasingtoe heating-snrhtce, in which case the plates are perpendicular to the tube, and'the tubes are so arranged as not to be in the saine vertical line.

I propose, under some circumstances, to modify the provision for presenting the products of combustion in my boiiel', by leading the whole up through the tubes B, and then leading down the partially-cooled gases, either spirally or in any other suitable manuel' around the exterior of the shell M` With any arrangcxent for. presentingr the hot gases to the exterior of the shell, the advantage of the eircular arrangement of' the pipes B and of the inclination of the several plates D, rising from the center outward in all directions, is obvious, because the current of rising steam and water, induced by the heating effect of the several pipes B, is, by such arrangement, combined with the heating ei'ect of the shell.

In case no heat is applied to the exterior M, the plates D may be inclined in the opposite direction, and the current of mingled steam and water may risc through the central space, assisted or not bythe heat 'of a tube or fi'ue in the center, which should have none of my cross-plates D. With that arrangement, the dense water will flow down between the exteriors of the plates D and the interior ofthe shell M. vFor stationary boilers, I much prefer the arrangement represented.

I am aware that many devices have been before proposed for variously promoting thea circulation of water in boilers, and for increasing the conducting or connecting surface; but I am not aware of any previous construction or arrangement similar, or,in its cfects, equal to mine. I can make my pipes very ety fectually by properly eoring, of east-iron, and, in such cases, propose to make the plates D in one piece, with the tubes B, to which theybclong. I can provide two or more series of tubes B, with their plates D, when the boiler is of s'niicient size to require them, in which' case the plates will be inclined in opposite direct-ions on the two sets of tubes.

I esteem it an important advantage of myinvcntion that it abstracts the heat from the gaseous contents ot the tubes with more than usual effect. lDhis is duc both to the presentation ci' the water in adense state and invery active currents, and also to the conducting eiiectof the plates D, and I believe it preferable, under most circumstances, to make the tubes B in a single series, and of such size as may be required to carry a large proportion of the draught of the furnace.

I have referred to the interpositien of soap-stone to defend the lower plate G, and have represented the tubes as double, er as enveloped each with a broad inclined thinible between eachA plate D, and the vnext above or below. Such would form a convenient mode of holding the'plates D, it1 not joined by solder, or the like, to the inner and main tubes B with sufficient force; but these provisions for reducing the transmission of heat may be objectionable where much steam is to be made in a small boiler, and can be entirely dispensed with without affecting the objects of my invention in any weakening or damaging degree.

I claim the within-described steam-boiler, composed of the pipes B, cross-plates D, and boiler-shell G H M, combined and arranged to serve relatively to each other and to thefluids circulating therein, substantially as herein set forth.

In testimony whcreofI have hereunto set my name in presence of two subscribing witnesses.

v SAML. D. TILTJMAN.-

Witnesses:

W. O. DnY, C. O. LrvINes.

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